This application claims priority to Japanese Applications No. Hei 11-312749 filed in Japan on Nov. 2, 1999, No. Hei 11-312750 filed in Japan on Nov. 2, 1999, No. Hei 11-312751 filed in Japan on Nov. 2, 1999, and No. He. 11-312752 filed in Japan on Nov. 2, 1999, the contents of which are incorporated by this reference.
1. Field of the Invention
The present invention relates to, and method of manufacturing of, a camera incorporating a finder unit and a photographic lens optical system each having variable power.
2. Description of the Related Art
In a conventional camera, generally, a finder optical system and a photographic optical system are designed as a pair. For example, for a photographic optical system having variable power, a finder optical system having variable power corresponding to a focal length range of the photographic optical system is used.
In recent years, a number of cameras and lens barrels having diversified zoom rates have been provided. If a special finder optical system is prepared to correspond to each photographic optical system in such cameras, there will be disadvantages in cost of parts, part management and the like, which prolongs development.
In case of assembly adjustment of the conventional finder optical system and photographic optical system, with the finder optical system fixed at a typical adjustment reference zoom position, the finder unit and the photographic optical system, set to a certain focal length, are adjusted or checked from standpoint of optical performance. The aforementioned adjustment reference zoom position refers to zoom wide end position or zoom tele end position.
Because in the conventional camera, only one zoom photographic optical system can be mounted on the finder optical system, the adjustment reference zoom position is always fixed to a predetermined position, so that the adjustment procedure is not troublesome.
However, because the finder optical system corresponds to the zoom photographic optical system one to one, the problems associated with product development, part cost and part management still exist if a finder optical system is made to correspond to a plurality of photographic optical systems.
Japanese Patent Application Laid-open (JP-A) No. 7-72543 has proposed a motor-driven lens shutter camera provided with a zoom lens. This camera is provided with a zoom encoder based on binary code so as to determine whether the lens barrel is located in a zoom section or accommodation drive section. If it is located in the zoom section, forward/reverse rotation of the zoom drive motor is changed over by a manual switch, and if it is located in the accommodation drive section, stop of power feed to the motor is inhibited.
In the camera disclosed in the above described Japanese Patent Application Laid-open (JP-A) No. 7-72543, to make a finder optical system correspond to plural photographic optical systems, the lens barrel has to be stopped at a target reference zoom position for adjustment and check on assembly process. However, the lens barrel is hard to stop at an accurate zoom position. Particularly, for the adjustment of variable magnification position of the finder unit relative to the zoom position of the lens barrel, the adjustment of interlocking with the electric flash unit or the like, the lens barrel has to be positioned more accurately. Therefore, a special electric control unit for adjustment needs to be prepared for the adjustment and check.
The present invention has been devised to solve the above described problems. According to the present invention, a finder optical system can correspond to a plurality of photographic optical systems, and therefore, an object of the invention is to provide a camera which shortens product development and reduces production cost. Another object of the invention is to provide a method for producing the camera which facilitates setting of adjustment positions of the finder optical system and photographic lens optical system and adjustment of the installation thereof.
In the camera according to the present invention, a first lens barrel has a first photographic optical system capable of changing magnification in a first variable magnification range and can engage the first photographic optical system at a predetermined variable magnification condition. A second lens barrel has a second photographic optical system capable of changing magnification in a second variable magnification range overlapping at least partially the first variable magnification range, and can engage the second photographic optical system at the predetermined variable magnification condition. The camera of the present invention comprises a camera main body allowing either the first lens barrel or the second lens barrel to be selectively installed thereon, a finder unit having a finder optical system capable of changing the magnification corresponding to the first variable magnification range and second variable magnification range and a finder engaging unit capable of engaging the finder optical system at a variable magnification condition corresponding to the predetermined variable magnification condition. When the camera of the present invention is assembled, the first and second lens barrels are engaged at the predetermined variable magnification condition and at the same time, the finder unit is engaged at a variable magnification condition corresponding to the predetermined variable magnification condition.
The manufacturing method of camera of the present invention comprises the steps of: selecting any one of plural photographic optical systems each having different variable magnification range; installing a lens frame unit corresponding to a variable magnification range of the selected photographic optical system on the camera main body; engaging the lens frame unit at a predetermined variable magnification condition; engaging a finder unit having a finder optical system having variable magnification capacity corresponding to a variable magnification range possessed by the plural photographic optical systems corresponding to the predetermined variable magnification condition; installing the finder unit to the camera main body; and releasing an engagement between the lens frame unit and finder unit.
Other features and advantages of the present invention will be apparent from the following description.